Means for cooling tools and removing chips



Dec. 20, 1938; w, HART 2,146,838

MEANS FOR COOLING TOOLS AND REMOVING OHIPS Filed April 13, 1936 A Em INVENTOR I mill d)?! f7. Hari. A Y I 204 v IATTORNEYS.

Patented Dec. 20,

UNITED STATES amass MEANS roa coonmc TOOLS AND minnow me cmrs William A. Hart, Detroit, Mich., assignor to Colonial Breach Company, Detroit, Mich a corporation of Michigan Application April 13, 1936, Serial No. 74,123

1 Claim.

The present invention relates to machine tools, and in particular provides an improved method of, and means for supplying liquid to a cutting tool to cool, lubricate, and clear chips from the a tool.

Objects of the present invention are to provide an improved system for and method of supplying a liquid having cooling and lubricating properties to a cutting tool; to provide such a method i and system which may readily be applied to and practiced in connection with the use of existing machines; and to provide such a method and system which are simple, economical, and positive and effective in results,

Further objects of the present invention are to provide a method of supplying cooling, lubricating, and chip clearing media to a cutting tool, which comprises feeding the tool from two sources, one of which supplies a relatively large 39 volume at a relatively low pressure, thus serving to lubricate and to maintain the temperature of the cutting tool and the work piece being operated upon below a predetermined limit, and the other of which supplies a relatively limited quantity at a relatively high pressure, and thus serves to wash away the chips collected during the cutting operation; to provide such a method in which the volume supplied at high pressure is so related to that supplied at low pressure that the latter is 80 not washed away by the former, while permitting the former to be of large enough volume to effectively clear away all collected chips.

Further objects of the present invention are to provide a system, as above stated, embodying related nozzles, one of which supplies liquid to the cutting tool in relatively large volume at relatively low pressure, thus bathing the tool and the work piece, lubricating them, and maintaining the temperature thereof at a low value, and the other of which supplies liquid to the cutting tool in relatively small volume at relatively high pressure, to thereby effectively wash away the chips from the tool; to provide such a system embodying a pair of concentrically disposed nozzles, the

outer one of which is disposed to supply a relatively large volume of liquid at low pressure and the inner one of which is disposed to supply a relatively small volume of liquid at relatively high pressure; to provide such a system in which the individual nozzles are supplied from fluid pressure pumps individual thereto, one of the pumps beingdisposed to pump relatively large volumes at low pressure and the other being disposed to deliver relatively low volumes at relatively high pressure.

Further objects and advantages of the present construction appear in the following description of the preferred but illustrative embodiments of the present invention shown in the accompanying drawing, throughout the several views of which corresponding reference characters are used to designate corresponding parts and in which:

Figure 1 is a perspective view of a broaching machine embodying the present invention;

Figure 2 is a fragmentary view in vertical section, taken along the line 2-2 of Fig. 1, showing one nozzle construction; and

Figure 3 is a fragmentary view in vertical section, showing a modified nozzle construction.

Partly by way of illustration, and partly because the improved cooling, lubricating, and chip removing method and system of the present invention are particularly adapted to solve problems which have heretofore caused serious difficulty .in the operation thereof, the present in- 951? vention has been illustrated as applied to a breaching machine. In the operation of these machines, work is customarily supported in stationary relation, and the broaching tool, secured upon a ram or other actuating member, is drawn across the surface of the work, or through an opening in the work, as the case may be. It will be understood that the broaching tools usually comprise an elongated member, having a plurality of spaced teeth formed thereon, of progressively increasing depth from the forward end of the tool to the rear end thereof.

Considering the drawing in detail, the machine, designated as a whole as '10, may be of generally conventional construction, comprising the frame 35 or housing l2, formed to provide ways it, upon which the broach head assembly I6 is vertically slidable under the influence of the ram l8; and the work table 20, upon which the work to be broached may be positioned. The broach 22, which may be of conventional construction, is secured upon the face of the broach head IS.

The ram mechanism l8 may be, and preferably, is, constructed in accordance with the disclosure 5 of the co-pending application of the present ap- I plicant, Serial No. 42,619, filed September 28, 1935, and assigned to the assignee of the present application. For the purposes of the present disclosure, it is suflicient to note that the piston and 50 piston rod of the ram assembly are stationarily supported in the frame I! and that the ram cylinder is reciprocable thereon, suitable reversing valve mechanism being provided to selectively effect the up and down movements of the latter, ill

the cutting action being preferably effected during the down stroke of the broach.

Referring now to the elements of the disclosed machine to which the present invention is particularly directed, two pipes 24 and 26 extend from suitable pumps 28 and 30 individual thereto, and which are housed within the frame l2, to a position adjacent the working face of broach 22, and are there threaded into an improved nozzle structure 32. An inner wall 34 divides nozzle 32 into inner and outer passages, which, at the delivery end of the nozzle, form concentric outlets 36 and 38, the outer outlet 36 being in communication with the pipe 24 and the inner or smaller outlet being in communication with the smaller pipe 26.

It will be understood that the elevation and positioning of nozzle 32 relative to the broach 22 and the work table may be adjustable, and that in normal operation, nozzle 32 may be spaced, a matter of an inch or so from the breach, and also positioned just above the level of the work piece being operated upon by the broach, so that the liquid discharged therefromis delivered to the broach teeth just before engaging the work.

The pumps 28 and 30 for supplying the lines 24 and 26 respectively may be of conventional construction, such as gear pumps, and are illustrated as driven by a single: motor 69, which may also be utilized, if desired, to drive the pump mechanism associated with the ram i8. As previously stated, pump 28 is adapted to deliver a relatively large quantity of cooling liquid through pipe 24 under a relatively low head, and pump 30 is designed to deliver a relatively low quantity of liquid through pipe 26, at a relatively high head. With this arrangement, during operation of the machine, a relatively fine stream of relatively high velocity is directed against the broach through pipe 26 which forcibly washes away and effectively removes any chips which may have collected between the broach teeth. At the same time, a relatively large quantity of cooling liquid is delivered under relatively low pressure through the pipe 24, which relatively large quantity is effective to prevent overheating of the broach and 2,14o,aas

to lubricate it. In a sense, the two supplies of cooling liquid thus perform individual functions; that is, the smaller high velocity stream performs a chip removing function and the larger relatively low velocity stream performs a cooling and lubricating function. As it will be understood, the relative rates of flow and relative velocities of the streams are such that the cooling and lubricating liquid is not swept from the broach by the fine stream from pipe 26. In practice, the described arrangement has been found to materially improve the operation of the machine, with a noticeable economy in the amount of liquid which it is required to pump for each cycle of the machine.

As an alternative to the integral nozzle construction described above, the modified construction shown in Figure 3 may be used, in which the cooling pipe 24 is threaded into a nozzle 42, the cooling pipe 28 being secured to the base thereof with the nozzle outlet and the latter pipe outlet similarly directed by the clip 44.

Although specific embodiments of the present invention have been described, it will be understood that the invention may be practiced in alternative ways, and that modifications in the form, number and arrangement of parts may be made in the particular structure within the spirit and scope thereof.

What is claimed is:

Mechanism for coolingand/or lubricating and for removing chips from a cutting tool of a broaching machine, comprising in combination a first pipe, a second pipe; means adapting both of said pipes to discharge upon a predetermined area on the surface of said cutting tool; and concurrently operated supply means associated with said pipes for discharging a relatively high volume of liquid through one of said pipes at low pressure and for at the same time discharging a relatively low volume of liquid through the other of said pipes at relatively high pressure, so that said tool is subjected to the simultaneous action of two streams of liquid.

WHLIAM A. HART. 

